Implement GetExecutablePath for Solaris

src/os.cc

@@ -61,7 +61,25 @@ const char path::preferred_separator;
 
 #ifndef _WIN32
 
-#ifdef __APPLE__
+# if defined(__linux__)
+
+// Linux implementation.
+path mp::GetExecutablePath() {
+  fmt::internal::MemoryBuffer<char, BUFFER_SIZE> buffer;
+  buffer.resize(BUFFER_SIZE);
+  ssize_t size = 0;
+  for (;;) {
+    size = readlink("/proc/self/exe", &buffer[0], buffer.size());
+    if (size < 0)
+      throw SystemError(errno, "cannot get executable path");
+    if (static_cast<size_t>(size) != buffer.size()) break;
+    buffer.resize(2 * buffer.size());
+  }
+  const char *s = &buffer[0];
+  return path(s, s + size);
+}
+
+# elif defined(__APPLE__)
 
 // Mac OS X implementation.
 path mp::GetExecutablePath() {
@@ -79,36 +97,27 @@ path mp::GetExecutablePath() {
   return path(s, s + size);
 }
 
-#else
+# elif defined(__sun)
 
-// Linux implementation.
+// Solaris implementation.
 path mp::GetExecutablePath() {
-  fmt::internal::MemoryBuffer<char, BUFFER_SIZE> buffer;
-  buffer.resize(BUFFER_SIZE);
-  ssize_t size = 0;
-  for (;;) {
-    size = readlink("/proc/self/exe", &buffer[0], buffer.size());
-    if (size < 0)
-      throw SystemError(errno, "cannot get executable path");
-    if (static_cast<size_t>(size) != buffer.size()) break;
-    buffer.resize(2 * buffer.size());
-  }
-  const char *s = &buffer[0];
-  return path(s, s + size);
+  return path(getexecname());
 }
 
-#endif
+# else
+#  error GetExecutablePath is not implemented for this system
+# endif
 
 // POSIX implementation.
 
 path path::temp_directory_path() {
   const char *dir = std::getenv("TMPDIR");
   if (!dir) {
-#ifdef P_tmpdir
+# ifdef P_tmpdir
     dir = P_tmpdir;
-#else
+# else
     dir = "/tmp";
-#endif
+# endif
   }
   return path(dir);
 }
@@ -129,7 +138,7 @@ void mp::internal::MemoryMappedFileBase::unmap() {
     fmt::report_system_error(errno, "cannot unmap file");
 }
 
-#else
+#else  // _WIN32
 
 // Windows implementation.
 
@@ -197,4 +206,4 @@ void mp::internal::MemoryMappedFileBase::unmap() {
     throw WindowsError(GetLastError(), "cannot unmap file");
 }
 
-#endif
+#endif  // _WIN32